It didn’t take the Mariners long to replace Hisashi Iwakuma in their rotation.

The Los Angeles Dodgers had not even confirmed signing Iwakuma on Monday before the Mariners acquired lefty Wade Miley and reliever Jonathan Aro from Boston for lefty Roenis Elias and reliever Carson Smith.

“It was Plan 1-A,” general manager Jerry Dipoto said. “When Kuma opted to head for the Dodgers, this was the preferred route.”

Miley, 29, was 11-11 with a 4.46 ERA last season in 32 starts for the Red Sox after spending the three-plus previous years at Arizona.

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Dipoto was the Diamondbacks’ vice president for player personnel when they selected Miley with the 43rd overall pick in the 2008 draft.

Miley is guaranteed $15.6 million over the next two years, including a $500,000 buyout clause on a club option for $12 million in 2018.

“Wade provides stability to our rotation,” Dipoto said. “He takes his starts. We’re raising the floor. One way of the other, you’re going to have to throw 1,450 innings in a season and, hey, they have to come from somewhere.”

Aro, 25, is a right-handed reliever who spent most of last season at Triple-A Pawtucket before making his major-league debut with six appearances in two tours.

“We like Jonathan as a guy who has a chance to compete for some of those middle innings,” Dipoto said. “He is very similar in a lot of ways to Rafael Betancourt, who was with the Rockies.

“He has a good history of missing bats. He has a good history of throwing the ball over the plate.”

The price wasn’t cheap.

Smith, 26, compiled a 2.31 ERA last season in 70 appearances and spent part of the year as the club’s closer. Elias, 27, is 15-20 with a 3.97 ERA in 51 games, including 49 starts, over the past two years.

“It was tough to give up Carson Smith,” Dipoto said. “We understand that. But without the ability to access the starting-pitcher market that we wanted to access, we needed to deploy something to make that happen.

“Carson Smith was the currency that got us to where we needed to be. He was the center point of the deal for the Red Sox. Wade, obviously, was the center point for us.”

The trade came less than a day after the Dodgers reached agreement with Iwakuma on a three-year deal for $45 million.

“We just weren’t willing to go to the third year,” Dipoto said. “We made that apparent early on. We were aggressive in what we did, and we went as far as we were willing to go.”

That’s not all.

The Mariners are also showing interest in Milwaukee first baseman/desginated hitter Adam Lind, a left-handed hitter who batted .277 last season with 20 homers and 87 RBIs in 149 games.

Lind, 32, is under contract next season for $8 million before becoming a free agent. The Brewers are seeking prospects, which could be a tough match; the Mariners’ farm system is thinly stocked at the upper levels.

Dipoto pointed to Miley’s workhorse resume as a key element in the trade.

“He takes his starts,” Dipoto said. “One of the issues we had with the extra year on Kuma was just not being able to press too firmly on the pencil with how far into that we could get.”

Another factor: The Mariners viewed the top free-agent alternatives — including Yovani Gallardo and Ian Kennedy — as likely to require a longer commitment and a higher salary.

The Mariners were also loathe to surrender their top draft pick, No. 11 overall, as the penalty for signing a player who received a qualifying offer from his former club.

Dipoto also said the club’s rotation is now fairly set. Miley will slot behind staff ace Felix Hernandez with Taijuan Walker, Nathan Karns and James Paxton projected to complete the five-man unit.

“We will continue to try to pad the lower level,” Dipoto said, “but this is the biggest starting pitcher acquisition that we’ll make.”

The Mariners, toward that end, have already signed right-hander Donn Roach to a minor-league contract that includes an invitation to big-league camp.

Roach turns 26 later this month and pitched primarily at Triple-A over the past two seasons, although he did make 16 appearances, including one start, for San Diego in 2014.

“Combine (Roach) with (Vidal) Nuno and Anthony Bass having the ability to stretch out and start games,” Dipoto said, “we feel that is some level of cover for the five-man rotation.”

The Mariners, in contrast, will seek to strengthen a bullpen weakened by Smith’s departure.

“In most free-agent markets,” Dipoto said, “the bullpen is the longest draw. There will be options. Somehow, between now and the start of the season, we will work toward acquiring as many options as we can.

“We feel that we have a good start with (Joaquin) Benoit, (Charlie) Furbush, (Tony) Zych, (Justin) De Fratus and Aro.”

SHORT HOPS

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